Targeting the BBB to treat CNS inflammation

项目2将确定如何靶向调节渗透性和极性的分子 中枢神经系统(CNS)内皮屏障影响神经炎症，通过 多发性硬化症(MS)小鼠模型的新神经成像方法。我们已经展示了 多发性硬化症病变中的内皮细胞表现出极性改变，表现为开拓性趋化因子 CXCL12沿管腔表面异常分布。白酒CXCL12通常用于限制 白细胞进入，而CXCL12的腔内表达与激活增加有关 其信号受体CXCR4在浸润性白细胞上的表达。我们证明了拾荒者 CXCL12受体CXCR7(也由中枢神经系统内皮细胞表达)是一种重要的调节因子。 白血球通过CXCL12的内化从肺表面进入。在初步研究中， 我们还发现，1-磷酸鞘氨醇(S1P)信号通过S1P2干扰血清白蛋白 CXCL12的表达，从而扰乱免疫豁免权。因此，靶向缺失的小鼠 S1P2或给予特定的拮抗剂JTE-013显示白细胞迁移减少 在EAE期间进入中枢神经系统实质。我们假设细胞膜极性的改变 中枢神经系统内皮细胞屏障上的CXCL12促进白细胞捕获和迁移到中枢神经系统， 有助于建立复发-缓解形式的中枢神经系统疾病周期 自身免疫力。我们已经确定了几个调节这一过程的分子，导致 逆转定位线索CXCL12的顶基表达。在这项提案中，我们将 探讨CXCR7和S1P2在中枢神经系统淋巴细胞转运和炎症中的作用 使用包括双光子活体内成像在内的新成像方式的自身免疫性疾病 显微和纵向使用扩散基谱成像(DBSI)，这 区分和量化活体小鼠的细胞密度和水肿(见项目1)和 尸检多发性硬化症患者和对照中枢神经系统组织。 我们预计DBSI比Gd增强对炎症更敏感，包括在 设置不太严重的血脑屏障改变。要确定两国之间的关系 内皮细胞和免疫细胞(Th1和Th17)的相互作用和BBB完整性的丧失，我们将 直接比较活体成像与DBSI和Gd增强的结果 动物。解决内皮细胞极性和定位信号的机制 通过与炎性细胞的相互作用，我们将利用体外和原位方法 人体组织。因此，目标1将决定CXCR7是否介导CXCL12的内化 在EAE期间需要Th1细胞对Th17细胞的渗透。目标2将确定S1P2是否- 介导的内皮细胞极性逆转导致T细胞捕获和进入增加 EAE和AIM 3将研究CXCR7和S1PR2激活与T细胞的关系 密歇根州BBB的迁移项目2的实验设计将如何定义DBSI 测定不同程度血脑屏障异常时的细胞和水肿变化 和EAE小鼠的细胞浸润。

Project 2 will determine how targeting molecules that regulate permeability and polarity at central nervous system (CNS) endothelial barriers impacts neuroinflammation, as assessed via novel neuroimaging modalities with murine models of multiple sclerosis (MS). We have shown that endothelium in MS lesions exhibits altered polarity, displaying the abluminal chemokine CXCL12 aberrantly along luminal surfaces. Abluminal CXCL12 normally serves to limit leukocyte entry whereas luminal expression of CXCL12 is associated with increased activation of its signaling receptor CXCR4 on infiltrating leukocytes. We showed that the scavenging CXCL12 receptor, CXCR7 (also expressed by CNS endothelium), is a critical regulator of leukocyte entry via internalization of CXCL12 from abluminal surfaces. In preliminary studies, we have also found that sphingosine 1-phosphate (S1P) signaling via S1P2 disturbs abluminal expression of CXCL12, which then disrupts immune privilege. Thus, mice with targeted deletion of S1P2 or administered a specific antagonist, JTE-013, show reduced migration of leukocytes into the CNS parenchyma during EAE. We hypothesize that alterations in membrane polarity of CXCL12 at CNS endothelial barriers promote leukocyte capture and migration into the CNS, contributing to the establishment of disease cycles in relapsing-remitting forms of CNS autoimmunity. We have identified several molecules that regulate this process, leading to reversal of apicobasal expression of the localizing cue, CXCL12. In this proposal, we will examine the roles of CXCR7 and S1P2 in lymphocyte trafficking and inflammation in CNS autoimmune disease using novel imaging modalities including two-photon intravital microscopy and longitudinally using Diffusion Basis Spectrum Imaging (DBSI), which distinguishes and quantitates cellularity and edema in live mice (see Project 1) and examination of autopsied human MS patient and control CNS tissues. We expect DBSI to be more sensitive than Gd enhancement to inflammation, including in the setting of less profound blood-brain barrier alterations. To determine the relationships between endothelial and immune cell (Th1 versus Th17) interactions and loss of BBB integrity, we will directly compare results utilizing intravital imaging to DBSI and Gd enhancement in the same animals. To address mechanisms by which endothelial cell polarity and localizing cues are induced by interactions with inflammatory cells, we will utilize in vitro and in situ approaches with human tissues. Thus, Aim 1 will determine whether CXCR7-mediated internalization of CXCL12 requires infiltration with Th1 versus Th17 cells during EAE. Aim 2 will determine whether S1P2- mediated reversal of endothelial cell polarity leads to increased T cell capture and entry during EAE, and Aim 3 will examine the relationship between CXCR7 and S1PR2 activation and T cell migration at the BBB in MS. The experimental design of Project 2 will define how DBSI determined cellularity and edema changes responding to various degrees of BBB abnormality and cell infiltration in EAE mice.